Unveiling the molecular architecture of the mitochondrial respiratory chain of .

is a ubiquitous free-living amoeba that can cause severe infections in humans. Unlike most other organisms, possesses a "complete" mitochondrial respiratory chain, meaning it con-tains several additional enzymes that contribute to its metabolic versa-tility and survival in diverse environments. This review provides a com-prehensive overview of the mitochondrial respiratory chain in , focusing on the key alternative components in-volved in oxidative phosphorylation and their roles in energy metabo-lism, stress response, and adaptation to various conditions. The func-tional characterization of the alternative oxidase (AOX), uncoupling pro-tein (UCP), and alternative NAD(P)H dehydrogenases, highlight their roles in reducing oxidative stress, modulating proton gradients, and adapting to changes in temperature and nutrient availability. These pro-teins and systems serve a role in the survival of under stressful conditions such as starvation and cold con-ditions. Further knowledge of the respiratory chain of the amoeba has potential implications for understanding the evolution of mitochondrial respiration and developing new therapies for treating infections.